Repetitive negative thinking and experiential avoidance have been hypothesized to be related, transdiagnostic maintenance factors for depression and anxiety. Work to date has not examined these maintenance factors in a comorbid clinical sample using a symptom-level approach. Adults presenting for treatment to an intensive CBT program (n = 492) completed measures of depression and anxiety symptom severity, repetitive negative thinking, and experiential avoidance. Permutation testing indicates that repetitive negative thinking improved the predictability of excessive worrying and concentration, whereas experiential avoidance improved the predictability of feeling like a failure, difficulties relaxing, and being afraid something bad was going to happen. Applying network analysis helps to more precisely identify which symptoms of depression and anxiety are associated with transdiagnostic maintenance factors, thus providing insight into how these factors may contribute to the maintenance of co-occurring disorders.